Opencode systems (OC) Ltd. and the “Intelligent Communication Infrastructure Laboratory” (ICI Lab) of the R&D&I Consortium at Sofia Tech Park have started the development and implementation of an Open Radio Access Network (Open RAN) Testbed.

Major part of the mobile network infrastructure is the Radio Access Network (RAN), where the basic components are the base stations. A base station, like any radio, has a Radio Frequency (RF) part and a Baseband (BB) part. For many years these two parts have been tightly integrated. Around 2011 distributed BSs appeared consisting of a base band unit (BBU) and remote radio units (RRUs). In addition, in the last few decades, RANs have shifted from analog to digital, in which hardware components have been replaced by software solutions that allow the implementation of flexible software-defined functionalities.

However, despite the digitalization and physical separation of these two parts, connecting the RRU of one provider to another provider’s BBU is usually not possible due to the proprietary of the solutions. This is a serious limitation for mobile operators in the process of equipment selection for the development of their networks and introduction of new technologies.

Following these driving forces the base station architecture has also evolved considerably over the last years towards the so called “Open RAN”. The main idea behind “Open RAN” is to make the RRU and BBU of cellular base stations independent and ​​to develop a way to build an open standard with open software for the interfaces and interaction procedures between the different elements of the base station. Thus, applying the “white box” approach, base stations can be assembled using hardware and software from different vendors, i.e. components from different vendors can be connected in the same base station. Currently, service providers worldwide are encouraging the adoption of Open RAN for 5G, because expectations are that, like the development of popular kit platforms such as Rasberry PI, the Open RAN component market can reveal significant innovations in the cellular network.

Aiming at the realistic validation and testing of 5G innovative solutions and applications Opencode Systems Ltd and the ICI Lab of the R&D&I Consortium at Sofia Tech Park have started the implementation of an Open RAN testbed The main goal behind this joint initiative is to better understand the practical implementation of this technology, its characteristics and constraints, in order to build up a sound foundation and relevant expertise allowing up-to date research and implementation of novel multi-user and multi-application 5G solutions.